An aneurysm is a ballooning of the wall of an artery resulting from the weakening of the artery due to disease or other conditions. Left untreated, the aneurysm will frequently rupture, resulting in loss of blood through the rupture and death.
Aortic aneurysms are the most frequent form of arterial aneurysm and are life threatening. The aorta is the main artery, which supplies blood to the circulatory system. The aorta arises from the left ventricle of the heart, passes upward and bends over behind the heart, and passes down through the thorax and abdomen. Among other arterial vessels branching off the aorta along its path, the abdominal aorta supplies two side vessels to the kidneys, the renal arteries. Below the level of the renal arteries, the abdominal aorta continues to about the level of the fourth lumbar vertebrae (or the navel), where it divides into the iliac arteries. The iliac arteries, in turn, supply blood to the lower extremities and perineal region.
It is common for an aortic aneurysm to occur in that portion of the abdominal aorta between the renal arteries and the iliac arteries. This portion of the abdominal aorta is particularly susceptible to weakening, resulting in an aortic aneurysm. Such an aneurysm is often located near the iliac arteries. An aortic aneurysm larger than about 5 cm in diameter in this section of the aorta is ominous. Left untreated, the aneurysm may rupture, resulting in rapid, and usually fatal, hemorrhaging. Typically, a surgical procedure is not performed on aneurysms smaller than 5 cm because presently no statistical benefit exists in performing such procedures.
Aneurysms in the abdominal aorta are associated with a particularly high mortality rate; accordingly, current medical standards call for urgent operative repair. Abdominal surgery, however, results in substantial stress to the body. Although the mortality rate for an aortic aneurysm is extremely high, there is also considerable mortality and morbidity associated with open surgical intervention to repair an aortic aneurysm. This intervention involves penetrating the abdominal wall to the location of the aneurysm to reinforce or replace the diseased section of the aortic aneurysm. A prosthetic device, typically a synthetic tube graft, is used for this purpose. The graft serves to exclude the aneurysm from the circulatory system, thus relieving pressure and stress on the weakened section of the aorta at the aneurysm.
Repair of an aortic aneurysm by surgical means is a major operative procedure. Substantial morbidity accompanies the procedure, resulting in a protracted recovery period. Further, the procedure entails a substantial risk of mortality. While surgical intervention may be indicated and the surgery carries attendant risk, certain patients may not be able to tolerate the stress of intra-abdominal surgery. It is, therefore, desirable to reduce the mortality and morbidity associated with intra-abdominal surgical intervention.
In recent years, apparatus and methods have been developed attempting to treat an aortic aneurysm without the attendant risks of intra-abdominal surgical intervention. Among them are inventions disclosed and claimed to endovascular and endoluminal prosthetics. These prosthetics appear to be promising but are significantly restricted. Primarily, current prosthetics are limited by the prosthetic's degree of similarity to the diseased vascular or luminal vessel the prosthesis will replace. The size, location, position, and specific geometry of the aortic aneurysm, however, is dependent on an individual patient and very often, aortic aneurysms occur in close proximity to, if not along, lateral branching vessels. The specific geometry between the abdominal aorta and iliac arteries, and extent of disease infestation, and the integrity of the vessel wall are often determinant factors in the availability and use of known prosthetics.
Besides being able to accommodate size, location, position, and specific geometry of a patient's aneurysm, the prosthetic needs to be positioned appropriately within the vessel containing the aneurysm to a branch vessel for sealing purposes. In order to position the prosthetic graft to accommodate the branching vessels, the use of anchoring members, expandable support grafts, radially expandable regions, trunk sealing cuffs, and the use of hardening agents have tried solve this problem. The variability between patients, however, is a limiting factor.
Current mechanisms to solve the positioning problem fall short in adapting to the individual patient, which results in inefficient and ineffective prosthetics. Additionally to position the prosthetic graft, the graft may need to be moved anteriorly or posteriorly once inserted. Known positioning mechanisms fail to provide a way to allow for adjustment of the prosthetic graft around the branching vessel area. Similarly, known positioning mechanisms may require a short occlusion of blood flow, although the occlusion of blood flow results in irreparable damage to tissues and organs. Hence, although in recent years certain techniques have been developed that may reduce the stress, morbidity, and risk of mortality associated with surgical intervention to repair aortic aneurysms, none of the systems that have been developed effectively treat the aneurysm and exclude the affected section of aorta from the pressures and stresses associated with circulation.
What is needed, therefore, is a variable expansible member system that provides an adjustable surface to be moved and size to be increased or decreased wherein an object within a vessel can be maneuvered into a position where further manipulations of the object can be employed. Specifically, the variable expansible member system could be used to maneuver a prosthetic aortic graft anteriorly or posteriorly during a surgical procedure. The variable expansible member system may also be used, for example, to maneuver a prosthetic graft such that the graft can be attached around an orifice of a branching artery where flow is essential to the function of critical organs.
It is therefore an advantage of some, but not necessarily all, embodiments of the present invention to provide a variable expansible positioning apparatus for maneuvering an object within a vessel.
It is another advantage of embodiments of the present invention to provide an apparatus for maneuvering the position of a surgical component, such as a prosthetic graft, for attachment to a vessel wall.
It is yet another advantage of embodiments of the present invention to provide an apparatus for maneuvering a surgical component for attachment around an orifice of a branching artery.
It is another advantage of embodiments of the present invention to provide an apparatus for positioning a surgical component without occluding blood flow.
Additional advantages of various embodiments of the invention are set forth, in part, in the description that follows and, in part, will be apparent to one of ordinary skill in the art from the description and/or from the practice of the invention.